Gameplay elements are rarely designed with narrative in mind. They're limited in quantity and tend to be blunt instruments; the mechanics of walking and jumping can only go so far in conveying complex stories. Given this limited scope, it's not surprising that gameplay is rarely used as the main vehicle for narrative.

UIV is the story of the Stranger's rise to embody eight virtues principal to the game's setting: honesty, compassion, valor, justice, honor, sacrifice, spirituality, and humility. On the surface, it's a typical CRPG of the era: there's exploration, statistical progression, item management, NPC conversations, and combat. The twist is how these elements are cleverly subverted for storytelling purposes.

Fairly common RPG activities such as opening random treasure chests, running away from battle, and being a smart alack to NPC's can lower various virtue-scores.

Conversely, overpaying for goods (instead of haggling down their prices), letting monsters escape from battle (and losing potential experience points), and destroying the most powerful artifact in the game (which makes combat a breeze), increase virtue. A full list of these virtue-altering actions can be found here.

UIV's main quest involves traversing the world in order to recover 8 virtue stones and runes, learn the mantras corresponding to each virtue, max-out all 8 virtue-scores, meditate at 8 virtue shrines, obtain the 3-part key, and finally discover the the word of passage.

Once these tasks are complete, the Avatar can descend into the abyss and place the virtue stones at their respective altars. A short quiz follows where the player is questioned about the virtues, and each correct answer displays a part of the codex-symbol. When the codex is fully unveiled, the player (presumably) gets to bask in its glory and return to the real world with newly gained knowledge and experience.

It's not an overly complex story, and its scant plot-points are almost entirely non-linear, but the narrative is closely coupled with the gameplay. UIV achieves this through various design choices.

First, the game gives a concrete role for the player to embody. It's all fine and good to "roll" a teetotaler, pyromaniac dwarf, but it's not nearly as much fun if this persona is restricted to the player's imagination. Becoming the Avatar is UIV's sole objective, so the entire gameworld naturally revolves around the player's ability to fill the Avatar's shoes. In addition, this is a perpetual task that encourages the player to stay in-character throughout the experience.

Secondly, UIV grafts virtue-fulfillment entirely onto existing systems. This makes the learning curve less harsh and presents interesting handicaps for familiar gameplay, e.g., avoiding hostile wildlife might not yield immediate rewards, but it aids in gradually achieving the larger goal of Avatar-hood. Since these systems are also granular, they encompass numerous ways in which the virtue scores can be affected.

Furthermore, the approach greatly reduces implementation costs. Every virtue-altering instance is not a custom, one-time cutscene, but rather an action that's optional and repeatable. In turn, the player can actively participate in the story by partially steering where, when, and how the virtues are tested. Since many events in the game also impact more than one virtue, the overall progression is quite open-ended.

Finally, the virtue system allows the player to fail. Hints are still dispensed throughout the game -- and can be actively sought out -- but it's not necessary to be aware of all the rules right from the start. There's no game over screen if virtue is lost; no invisible wall, or awkward text prompt, or an automatic checkpoint reload. The event is simply recorded, and retributions can be made later down the road.

This makes the path to Avatar-hood a potentially bumpy (and a more interesting) tale, and prevents the game from clumsily asserting itself and its limitations.

Lots more could have been done to polish the virtue system and to make it a larger part of the gameworld, but UIV remains notable for the way it allows the player to collaborate with a pre-existing script. This is also done largely through gameplay, and, at least in part, is the reason why so many people keepplayingit to this day.